With the rapid development of wireless communication technologies, the use of a filter is becoming more and more extensive. The filter is used to filter a signal, achieving an effect of signal recognition and noise reduction. A band-pass filter is one kind of filters. The band-pass filter is a device that allows waves of a particular frequency band to pass while shielding other frequency bands.
However, the design of an existing band-pass filter is relatively poor in wave transmission performance for electromagnetic waves, is poor in cut-off performance, and does not have good inhibition.
For a problem in the prior art that wave transmission performance of a band-pass filter is poor, currently, no effective solution is yet proposed.